Wire coil.



W. KELLER;

WIRE COIL.

APPLIOATION FILED :rtm1: s, 1905.

Patented Feb.28,1911.

WILHELM KELLER, OF FRANKFORT-ON.THEMAIN, GERMANY, ASSGN T0 THE FIR-M OF HARTMANN AND BRAUN', AKTIENGESELLSCHFT, OF FRANKFORTGNTHE MAIN, GERMANY.

assise.

, Winn Cori..

Patented llele.' 2S. 19kt.'

Application filed .Tune 8.1905. erial No. 64,297.

To all! whom i may concern:

y lle 1t known that I, Wiminn KELLER, a suhjeet of the German Emperor. and a resi- -t'raine have been Compressed.

have invented certain new and useful lui-` [n'ovenients in `Wire Coils. of which the following` is a 'speeitication 'lhere are many eases, particularly in cleclrieal measuring* nistrun'ients or devices., where it 1s desirable, that wire coils. either islationarir or movable', should` occupy the leastpossible space, in order to attain eera tain aflvantages, u-'hieh'niay vary according.; to the circumstances.

This invention relates to wire coils. and ,in partieular to wire coils used in'eleetrieal instrlunents where a light and compact coil is desirable.`

The object ot' this invention is to construct va coil whiehis compactI and light.

coil has been compressed. Fig. 7 is a cross section through a. part'ot' a uirel coil in one layer on a traine priorto the eo-nunession.

l Fig. 8 is a similar cross l section after the compression. Fig'.- 9 is n cross section through a part. ot' a wire coil in two layers on a Yt'ranie prior to the.'eoninressioin and Fig. l0 is asimilar cross section atler the compression.

Similar letters of reference reler to sintilar parts throughout the several views.

The covered or hare wires, from which the wire coils are made, may have any eross see tions, vhut they are preferably made round as usual. ln ease the coil initially ltorined troni hare Wires itl will he understood that, suitable insulating material will he applied to the coil and 1n the spaces between the wires before itis compressed, as liei .\i.iatt.e r described. lli/'hen several ivini'liugs l. l ot a wire coil are placed in a laye-r on a traine 2 bet-Ween the two (langes 3.3 of the latter in Fig. 7, an examination ot this figure will clearly show, that Vprior to the compression there will be. spaces 4, 4 filled 'with air be tween the sere `'al windings and the fraineand tiangres, also thatA the external face` of the coll 1s not smooth7 since 'furrows 5 are lett: between the several windings l, 1. The thieli'- ness ot' the wire eoil alone is liketliedianie` ter of the wire l and its insulation anelinoveove'r the thickness of the lframe 2 will have to he taken' into consideration. When. the windings 1, 1 of the coil are subjected to' a pressure of the requiredfa'mnnnt, the windings lean be so .much ompressed', as not only to reduce to naught the air spaces t, l hat also to render the face perfectly smooth, asI is shown at Fig'. 8,- Where the 'original shape ot lthe. windings is indicated bydotted eireles. Ot' course, also the frame :2 will be compr-seed in an irregular manner, as its thickness will he reduced the most. in the middle of eaeh winding 1. Fig. 8 clearly shows the reduction of the thielness of the Wire coil and the frame by the difference. between'- the smooth upper faceand the ini tial face yindicated by the dottedstraiglit line.

n Whe-n a wire coil is placed in two layers ot' windings 6,6011 a frame 7 between tivo flanges 8, 8 of course there will be' a greater number of air spaces between the several windings G., 6 and between tlieinand the traine 7 and langes 8, 8. To furtherreduee the thickness ot the wire coil and= the traine. the latter may he made of a comparatively sot't. material (for instance ainxninininl. 'lhenuinler the eonipression'the frame will also lie widened or stretched, so that it; at-V tains a `greater breadth than before, as is (deal-l",r shown at Fig. l0. 1Where so pre ferred, during the compression the two tlanges 8. S of the frame 'i' niay he lientl in the manner shown. The dotted straight line' in Fig. l0 'indicates the initial upper tace (see also Fig. 9); so that it will be apparent. houT great a reduction in the thickness ot' the eoi'l and traine can be obtained by the een i pression.

rEhe Compression may be etleeted in any lanen-'n press or similar machine tool with the aid ot' convenient molds or eonibination dies et' any known construction. The wire eoil may he, compressed either in a whole or in sections. lt depends uponl the kind of the wire coil. Whether it is to he comv pressed in several planes or partly in planes and partly in cylindrical faces or otherwlse.

eti

The frame, pattern or the like when einloyed may be of a convenient metal, either, hard or soft, or .it may be of any insulating material. .The molds or combination dies may`be so arranged as to either prevent the frame, pattern or the like from widening and lengthening or stretching under the compression, or to permit it to widen or to stretch either in one direction only or in l0 two dii'ections at right angles to each other. ,In any case the molds or combination .dies should be so arranged as to give the compressed wire coil, either alone or in combination with the frame, pattern or the like the desired shape as shown in Fig. 8. The

yworking faces of the molds or combination dies are preferably polished, so as to roduce on the compressed wire coils pei'- ectly s'niooth faces without any furrows or s aces,'so that` no dust nor fi rs may be a le to adhere. The so com )ressed wire ycoils will be found most suita le for eleetrical measuring instruments or devices with narrow permanent magnetic vfields Fig. 1 shows for example a wiiepcoil 14 wound in a single layer over a turnable rectangular frame with two sections l0, l0 and two sections t), 9 at right angles to each other. The frame is assumed to be made 80 of a sott metal such al aluminium. The molds or combination dies (not shown) of any known construction may be so arranged. that their respective parts anne in contact with the whole internal face ,of the frame and with the external faces of the coil 14. During the con'ipression of the wire coil liland the frame in anyknown n'ess or similar machine tool with the ai( of the said molds oi' combination dies the windings of 40 the coil ll will be mostly flattened and reduced in their thickness in a similar inanner as in Fig. 8, and at the same time the frame sections will be stretchdd in the cross direction only in a similar hianner as in t5 Fi .'10. The shape of the so compressed coi and frame is clearly shown at Fig. 2.'

Where so preferred, ot' course the molds or combination dies may' be so arranged, as to revent all sections of the frame faim osti'etching during thc compression.

Figs. 3 and 4 show a wire coil without any frame, pattern oil the like prior to the compression, as is clearly visible'in Fig. 5, which is a cross section through the line A-B in Fig. 4. Allier the compression the thickness of the coil will be reduced, as

is shown at Fig. 6. i

,Hitlierto I have shown two different wire `my method, either wholly or cameo coils, but it is obvious, that wire coils of every description, whether stationaryor movable, may be compressed according to partly. The ial point is, that all the air spaces between the windings bereduoad to nau ht and the thickness of thc'wire coil, eit er alone orl in combination with a, frame, pattern orthe like be reduced in the direction ofthe pressure exerted on the coil or the coil and the frame :so that the wire lcoil or the wire'coiland the frame'or the like occupyA compression fiat wire coils will also be rendered stiffer and more durable.

It is evident, that for a given number of windings a compressed wire of a greater cross section, that is of a smaller electrical resistance, may be employed, than if the wire weie left uncompressed, as the space ottered is too limited. Thus it is possible to employ for a given electrical resistance and a given number of windingsa wire from a metal of a smaller specific weight, than hitherto to lighten the coil-windiiig or to employ the wire from the said material for a given number of windings and a given weight of -tlie coil to reduce thtl electrical resistance. For a given cross section of the wire it is also wit-h the aid of the compression possible to considerably kincrease the number of windings in a coil to be arranged within a given space.

No claim is herein made to the method otl reducing the thickness of a wire coil described in the foregoing specification.

lVhat I claim as my invention, and desire to secure by Letters Patent, is-

4As an article of manufacture, an electrical instrument coil comprising a frame of soft material, insulated wire wound on said frame, said wire and frame heilig molded and compressed into a Isolid mass leaving no air spaces between the windings, the entire surface of the winding-being smooth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

lVILHELM KELLER. Witnesses Enwix DiriieL.. Miclmnr. Vonk. 

